The redfield you are looking at is not an AO scope. This will cause parellex problems at any distance other than what it's set at.
Look at the Mueller APV. You can get them for $130 to $150 delivered.
4 X 14 X 40, AO. Very sharp for the price, lifetime warrenty.
They are great scopes. You have to pay at least twice as much to find a better one. I have one on my BRJ Savage MKII that I had accurized by Savagegunsmithing and I've shot a best of .117" 5 @ 50 yds and it shoots in the .1"'s with ease on a good day. The scope is plenty good enough to allow that kind of accuracy. They are the best deal going.
If you want to just shoot paper, for about $225., you can get the Mueller 8 X 32 X 42 AO scope. It has a side focus/parrellex adjustment knob.
Another great scope for the money.
The Redfields are nice, but the one's your looking at without parellex adjustment will cause your groups to really enlarge at anything other than the 75 yd parellex they are set at.